Shocking new data released by the GMB union yesterday revealed the full scale of financial punishment dealt to ordinary people since City speculators brought Britain to its knees in 2008.

Average pay plunged in real terms by 13.8 per cent between April that year and November 2013. But the headline rate concealed massive differences.

Workers in London's Hammersmith and Fulham have seen 49 per cent of their wages wiped out in just five and a half years.

On average pay in the capital was down by a fifth.

Among other areas hardest hit were Warrington in Cheshire, where wages plummeted by nearly a quarter, from £28,366 to £26,607 in cash terms.

Sheffield in South Yorkshire saw an average £1,470 sliced from pay packets - a 23.9 per cent real-terms drop when inflation is taken into account.

And workers in Blackpool, Hartlepool, Portsmouth, Perth and Kinross, Oldham, Swindon and Walsall all lost at least a fifth of their wages.

The union compiled the figures using official data contained in the Office for National Statistics annual survey of hours and earnings.

In April 2008 the UK average was £26,137.

Five years and six months later it stood at £27,174.

But the 4 per cent rise was wiped out by inflation over the same period of 17.8 per cent.

GMB general secretary Paul Kenny said the figures showed the true scale of the attack on working people as the British economy has faltered.

"These alarming figures show how hard-pressed working people across the UK are struggling to pay their bills after years of wage decline and attacks on the living standards of families throughout the land.

"Working people deserve and need a decent pay rise to halt the drop in living standards."

In a stark contrast bosses' organisation the CBI director-general John Cridland said his members had a "spring in their step."

Despite the explosion in part-time work revealed in this month's employment figures, he claimed that full-time jobs were being created and that businesses' greatest challenge was now "to deliver growth."